Definition
The MBS value stream textbook goes from five-level PSI (marketing, sub-base, factory, components, key materials) to N-point order release, then to three upstream scheduling modes: follow (Task 1 derived from 1, fixed lead time = production cycle + Safety Stock), order-based (with latest inbound time), and shared (upper limit set by takt cycle, system consolidates demand; textbook p9 calls this one a "supermarket"). Not a DBS standard.
In detail
Point N is the start of the last continuous flow; production instructions are issued only here. Upstream processes receive kanban at N−x according to their respective lead times. Follow mode applies only when sequence is consistent, lead time is fixed, and upstream 1 matches 1 or is mixed-flow with capacity greater than downstream; order-based mode relies on latest inbound time, sharing relies on inventory caps; the three cannot be mixed for the same process pair. p90–p91 use the same set of final assembly tasks to demonstrate how the two modes derive make-to-order tasks.
Example in practice
Welding line and assembly line task sequence are consistent, lead time fixed at 3.5 hours, ABS determines follow mode is applicable: welding 6:30 start corresponds to assembly 10:00; another upstream process capacity is less than assembly, switch to order tracking, system back-calculates latest warehouse-in time 9:30 based on assembly start time and reconciles.